Field
The present invention relates to micro devices. More particularly embodiments of the present invention relate to a method and structure for receiving a micro device on a receiving substrate.
Background Information
Integration and packaging issues are one of the main obstacles for the commercialization of micro devices such as radio frequency (RF) microelectromechanical systems (MEMS) microswitches, light-emitting diode (LED) display and lighting systems, MEMS, or quartz-based oscillators.
Traditional technologies for transferring of devices include transfer by wafer bonding from a transfer wafer to a receiving wafer. One such implementation is “direct printing” involving one bonding step of an array of devices from a transfer wafer to a receiving wafer, followed by removal of the transfer wafer. Another such implementation is “transfer printing” involving two bonding/de-bonding steps. In transfer printing a transfer wafer may pick up an array of devices from a donor wafer, and then bond the array of devices to a receiving wafer, followed by removal of the transfer wafer. Some printing process variations have been developed where a device can be selectively bonded and de-bonded during the transfer process. In both traditional and variations of the direct printing and transfer printing technologies, the transfer wafer is de-bonded from a device after bonding the device to the receiving wafer. In addition, the entire transfer wafer with the array of devices is involved in the transfer process.
Other technologies for transferring of devices include transfer printing with elastomeric stamps. In one such implementation an array of elastomeric stamps with posts matching the pitch of devices on a source wafer are brought into intimate contact with the surface of the devices on the source wafer and bonded with van der Walls interaction. The array of devices can then be picked up from the source wafer, transferred to a receiving substrate, and released onto the receiving substrate.